Russia's deputy foreign minister has called on the United States and Europe to take "serious" steps to combat terrorism, warning that several Middle Eastern countries are threatened.

"Russia will not stand idle toward attempts by terrorist groups to spread terrorism in regional states," Sergei Ryabkov told reporters Saturday during a visit to Damascus, apparently referring to the rapid advance of the extremist Islamic State of Iraq and the Levant (ISIL) across eastern Syria and northern Iraq.

He praised Damascus' "responsible" decision to give up its chemical weapons, saying that doing so has boosted Syria's security.

On Monday, Syria finished handing over to Western powers 1,300 tons of chemical weapons it acknowledged possessing, completing a deal reached last fall under threat of US airstrikes.

The developments in Syria are being overshadowed by the unrest in neighboring Iraq where the ISIL, one of the main militant forces in Syria, has been killing scores of civilians and army soldiers to occupy more lands.

Since the foreign-charged war in Syria started more than three years ago, the United States has provided widespread political and military support to the militant groups to help them overthrow the government.

Earlier this month, US National Security Advisor Susan Rice acknowledged that the Pentagon was also delivering "lethal" support.

The foreign-sponsored insurgency in Syria, now in its fourth year, has reportedly killed almost 160,000 people. Nearly three million Syrians have fled the country.